1. Field of the Invention
The present invention relates to extraction of clock information which is particularly suitable for recovering clock pulses from signals corrupted by noisy channels such as high density recording mediums.
2. Description of the Related Art
With continued advances in high density recording technology, there is a need to recover data signals from noisy channels with as low a bit error rate as possible. Partial response maximum likelihood sequence estimation, which has been used in communication systems, is currently under study as a new technology for detecting signals from high density recording mediums. However, the clock frequency spectrum of the signals has no sufficient signal-to-noise ratio for properly operating a conventional phase-locked loop and sampling jitter results. Although partial response maximum likelihood sequence estimation is theoretically powerful for recovering data from high density discs, its performance will be limited if the recovered clock is affected with jitter.
Accordingly, there exists a need for recovering jitter-free clock information from distorted signals.